Generating sleepers for railroad track
Array modifier springs to mind as sleepers are somewhat of an array. It does however depend upon the way you want to extract (excuse my use of language, English is not my native language) your track.

If you intend to make some straight track, I would first create the tracks, 60 cm looks kind of right. Create a sleeper next and join it all as one object (sleeper as "root" works fine for me). I hope the included pictures enlighten you a little.



A straight track might look like this and can use an relative interval of 1:



To create a curve, this method is to crude: you get a lot of jagged connection, though if the track is only a very minor part of your scene, it might work. I reduced the interval to 0.95 to avoid gaps in the outside curve.



As you may see from my examples, I replaced your nice track-profile with a fairly crude modified cube.

I hope this helps you a little, kind regards, Christiaan